In some plasma processing systems, multiple radio frequency (RF) signals are provided to one or more electrodes within a plasma chamber. The RF signals help generate plasma within the plasma chamber. The plasma is used for a variety of operations, e.g., clean substrate placed on a lower electrode, etch the substrate, etc.
Between a driver and amplifier system that generates a radio frequency (RF) signal and the plasma chamber, an impedance matching circuit is usually placed. The impedance matching circuit matches an impedance of a load, e.g., plasma within the plasma chamber, with an impedance of a source, e.g., the driver and amplifier system that generates the RF signal. However, in certain situations, the impedance matching is not quick enough to respond to a change in the plasma impedance.
Moreover, although some systems are quick enough to respond to the change, these systems may not result in accurate adjustment of power and/or frequency to stabilize the plasma.
It is in this context that embodiments described in the present disclosure arise.